If you're not sure who your DNS Provider is, you can use a service that offers a WHOIS lookup tool. We recommend the following:
> ICANN Registration Data Lookup
The ICANN registration data lookup tool allows you to check the current registration information for domain names and Internet number resources. This is useful if you don't know which registrar was used or need to find resources and support for managing your DNS configuration.
When you perform a search on the ICANN Registration Data lookup, it will provide you with several pieces of information including Domain Information, Contact Information (often times this is redacted for privacy), Administrative & Technical Contact Information, DNSSEC Information, Authoritative Servers, Notices, and Registrar information.